Glossary of EJSCREEN Terms
Demographic Indicators
- Percent minority
Percent minority as a fraction of population, where minority is defined as all but Non-Hispanic White Alone. Calculated from the Census Bureau's American Community Survey 2010-2014. - Percent low-income
Percent of individuals whose ratio of household income to poverty level in the past 12 months was less than 2 (as a fraction of individuals for whom ratio was determined). Calculated from the Census Bureau's American Community Survey 2010-2014. - Percent less than high school education
Percent of individuals age 25 and over with less than high school degree. Calculated from the Census Bureau's American Community Survey 2010-2014. - Percent in linguistic isolation
Percent of households in which no one age 14 and over speaks English "very well" or speaks English only (as a fraction of households). Calculated from the Census Bureau's American Community Survey 2010-2014. - Percent over age 64
Percent of individuals over age 64 as a fraction of the population. Calculated from the Census Bureau's American Community Survey 2010-2014. - Percent under age 5
Percent of individuals under age 5 as a fraction of population. Calculated from the Census Bureau's American Community Survey 2010-2014. - Demographic Index
The Demographic Index in EJSCREEN is a combination of percent low-income and percent minority, the two demographic factors that were explicitly named in Executive Order 12898 on Environmental Justice. For each Census block group, these two numbers are simply averaged together. The formula is as follows: Demographic Index = (% minority + % low-income) / 2. Calculated from the Census Bureau's American Community Survey 2010-2014.
Environmental Indicators
- Air Toxics Cancer Risk (NATA Cancer Risk)
Lifetime cancer risk from inhalation of air toxics, as risk per lifetime per million people. Source: EPA 2011 National Air Toxics Assessment - Air Toxics Respiratory Hazard Index (NATA Respiratory HI)
Air toxics respiratory hazard index (the sum of hazard indices for those air toxics with reference concentrations based on respiratory endpoints, where each hazard index is the ratio of exposure concentration in the air to the health-based reference concentration set by EPA). EPA 2011 National Air Toxics Assessments - Diesel Particulate Matter level in air (NATA Diesel PM)
Diesel particulate matter level in air in micrograms per cubic meter (µg/m3). Source: EPA 2011 National Air Toxics Assessments - Ozone level in air
Ozone summer seasonal avg. of daily maximum 8-hour concentration in air in parts per billion, 2012. Source: EPA Office of Air and Radiation - PM2.5 level in air
Particulate matter (PM2.5) levels in air, micrograms per cubic meter (µg/m3) annual average, 2012. Source: EPA Office of Air and Radiation - Traffic Proximity and Volume
Count of vehicles per day (average annual daily traffic) at major roads within 500 meters (or nearest one beyond 500 m), divided by distance in meters. Calculated from U.S. Department of Transportation National Transportation Atlas Database, Highway Performance Monitoring System, 2014, retrieved 4/2015. - Lead Paint Indicator (% pre-1960 housing)
Percent of housing units built before 1960, as indicator of potential exposure to lead paint. Calculated from the Census Bureau's American Community Survey 2010-2014. - Proximity to Major Direct Dischargers to Water
Count of National Pollution Elimination Discharge System (NPDES) major direct water discharger facilities within 5 km (or nearest one beyond 5 km), each divided by distance in km. Calculated from EPA PCS/ICIS database, retrieved 12/2015. - Proximity National Priority List Sites (NPL)
Count of proposed and listed NPL sites within 5 km (or nearest one beyond 5 km), each divided by distance in km. Count excludes deleted sites. Source: Calculated from EPA CERCLIS database, retrieved 11/2015. - Proximity to Risk Management Plan (RMP) Facilities
Count of RMP (potential chemical accident management plan) facilities within 5 km (or nearest one beyond 5 km), each divided by distance in km. Calculated from EPA RMP database, retrieved 11/2015. - Proximity to Treatment Storage and Disposal Facilities (TSDF)
Count of TSDF (hazardous waste management facilities) within 5 km (or nearest one beyond 5 km), each divided by distance in km. Calculated from EPA RCRAInfo database, retrieved 11/2015.
EJ Indexes
- EJ Index
The EJ index is a number that combines environmental and demographic information for a place. There is an EJ Index for each environmental indicator. The EJ Index highlights which block groups contribute the most toward low-income/ minority residents nationwide having a higher environmental indicator score on average than the rest of the US population. To calculate a single EJ Index for one block group, EJSCREEN multiplies the environmental indicator by demographic information. This demographic information includes percent low-income and percent minority (as the Demographic Index), and total population of the block group. This is the formula for the index:
EJ Index = (Environmental Indicator) X (Demographic Index for Block Group – Demographic Index for US) X (Population Count for Block Group)